import java.util.UUID;
import java.time.LocalDateTime;

public class Book{

    private static ArrayList<Book> library = new ArrayList<Book>();
    private String title;
    private UUID id;
    private static int bookCount = 0;
    private LocalDateTime enteredLib;

    public Book(String bookTitle){
        this.title = bookTitle;
        id = UUID.randomUUID();
        bookCount++;
    }

    public UUID getId() {
        return id;
    }

    public String toString(){
        return "Book title: " + title + "; id: " + id;
    }

   /*  public int getBookCount(){
        return bookCount += 1;
    }*/
    public static int getBookCount(){
        return bookCount;
    }


    public static void main(String[] args){
        Book book = new Book("The Book Thief");
        Book book2 = new Book("The Midnight Library");
        System.out.println(book);
        System.out.println(book2);
        System.out.println("Book Count: " + Book.getBookCount());

        
    }
}
Book.main(null);

Book title: The Book Thief; id: 3d90eaaa-3033-427b-81d8-1f5bec3f876d
Book title: The Midnight Library; id: 32d37f07-60aa-4b4b-9bbf-044269ba7d16
Book Count: 6

public class Novel extends Book{
    public String author;
    private int enteredLib;
    private String bookTitle;
    
    public Novel(String bookTitle, String author,int enteredLib){
        super(bookTitle);
        this.author = author;
        this.enteredLib = enteredLib;
    }

    public void setTitle(String bookTitle) {
        this.bookTitle = bookTitle;
    }
    
    public String getTitle() {
        return bookTitle;
    }


    public String getAuthor() {
        return author;
    }

    public int getEnteredLib() {
        return enteredLib;
    }

    public void setEnteredLib(int enteredLib) {
        this.enteredLib = enteredLib;
    }

    public static void main(String[] args) {
        Novel novel = new Novel("This Book", "Author", 12);

        System.out.println("Novel title: " + novel.getTitle());
        System.out.println("Novel author: " + novel.getAuthor());
        System.out.println("Novel time: " + novel.getEnteredLib());
    }
}
Novel.main(null);

Novel title: null
Novel author: Author
Novel time: 12

public class Textbook extends Book{
    public String pCompany;
    private int enteredLib;
    private String textbookTitle;
    
    public Textbook(String textbookTitle, String pCompany,int enteredLib){
        super(textbookTitle);
        this.pCompany = pCompany;
        this.enteredLib = enteredLib;
    }

    public String getCompany() {
        return pCompany;
    }
    public void setCompany(String pCompany) {
        this.pCompany = pCompany;
    }
    public void setTitle(String textbookTitle) {
        this.textbookTitle = textbookTitle;
    }
    
    public String getTitle() {
        return textbookTitle;
    }

    public int getEnteredLib() {
        return enteredLib;
    }

    public void setEnteredLib(int enteredLib) {
        this.enteredLib = enteredLib;
    }


    public static void main(String[] args) {
        Textbook textbook = new Textbook("This Textbook", "Company", 15);

        System.out.println("Textbook title: " + textbook.getTitle());
        System.out.println("Textbook author: " + textbook.getCompany());
        System.out.println("Textbook time: " + textbook.getEnteredLib());
    }
}
Textbook.main(null);

Textbook title: null
Textbook author: Company
Textbook time: 15